The species as originally defined was more comprehensive in its details than when printed; for the restricting "decussatim" had not been added, and "Gualt. t. 93. f. B." was an additional synonym. The printed additions were "obsoletis," "Margine reflexo," "exteriore duplicato longiore," and the final remark. _S. imbricatus_ was the intended name. C. HIPPOPUS. _Sp._ plicatus muricatus, ano retuso clauso dentato. "Arg. t. 26. f. H." was an additional synonym of the MS.: the printed 20 should have been 10, as written: "ut in præcedente" was an emendation: _S. asper_ was the proposed name. C. LAZARUS. _Sp._ imbricatus. Seba was not cited: "obliquam" followed "fossam" in the MS. "Elevatis," "longitudine testæ," "productiore," "instar auris" formed no portion of the early description. C. ANTIQUATA. _Sp._ subcordatus, sulcis perpendicularibus transversim striatis. No name was attached to the original details, which appear to have been altered ("in aliis minimum cordatum impressum fuscum"), and the synonym of Bonanni added, in order to comprise that species (_Cardita sulcata_) which had been pictorially defined in the 'Systema.' "Gibba" was preceded by "admodum": "obsoletis" was not present. _Cardita bicolor, var. unicolor_ was probably intended. C. SEMIORBICULATA. _Sp._ semiorbiculatus compressus, decussate striatus, rudis. "Interior" was the earlier reading of "primarius." C. CORDATA. _Sp._ cordatus, transversim striatus, hinc elongatus, compressus. C. OBLONGA. _Sp._ oblongus, antice angulatus, dentibus anticis acutis. "Unico" (error for "unicus") originally preceded "in altera valvula." C. CORDIFORMIS. _Buc._ subrotundum læve, umbonibus recurvatis. The brief description in the 'Systema' had evidently been copied in the manuscript by our author himself, who cited Gualt. t. 71. f. E. as the sole synonym. The specimen had apparently been added to the collection, subsequently to the drawing up of the first catalogue. ARCA. Testa crassa, umbonibus distantibus intus fornicatis. Cardo planus, masticatus dentibus numerosis minimis æqualibus transversis. A. TORTUOSA. _A._ oblonga obliqua, valvula altera oblique carinata. "Nates, &c." and "Cardo, &c." were the printed additions to the earlier description. The 'Systema' synonyms of Klein (t. 8. f. 16) and Bonanni (2. f. 128) were present in the manuscript. A. NOÆ. _A._ oblonga angulata hians. This manuscript furnishes us with the additional synonyms of "Aldrov. 3. p. 513." and "Sloan. Hist. 2. p. 257. Musculus Matthioli," besides the previously published references to Lister (368. n. 208) and Bonanni (2. t. 32). The formation of the hinge was not, however, indicated, and the passage commencing with "Nates" has been enlarged from "Umbones remotissimæ, area interjecta concava, ad angulum rectum striata. Margo exterior in medio hians, apertura barbata." The intended specific epithet was _A. Noemi_.